Coated paper.



JAMES Mimi, or 'ronon'ro, oi'rrnnro,

CANADA.

COATED PAPER.

Patented ma '7, acre.

film of glue that binds the very minute par- 1,265,351 Specification ofLetters Patent. No Drawing. Application filed. October 1917. Serialit'd-194,69

To all whom it may cancer n:

Be it known that I, J AMES MILN, a s ub ect of the Kingrof GreatBritain, res1dmg at the ,city of oronto, in the county of and Provinceof Ontario, Dominion 0 Canada, have invented certain new and useImprovements in Coated Paper; and I hereby declare that the following isa full, clear, and exact description of the same,

Ihe present invention relatesto a co ted paper which may be used inmechanical processes for the production of surfaces for rintingillustrations when such surfaces are adapted to be attached to printingcylinders or platens or to the lower surfaces of printing blocks in sucha-manner to be exerted upon the difierent parts of the sheet to" beprinted upon is regulated accordlhe preferred solutionof bleaching powetch on the We g the hyp the color may ing to the light and and theinvention paper surface. a coating of etchable material, which, afterthe impression of the picture is subjected whereby, the high lights leftuncovered or lightly covered by be more or less deeply or etched by theaction of the etchcompletely 7 washlng or brushing agent, and removed bySatisfactory results are obtainable by applying to the surface of thepaper an etc able body capable of dissolution when subjectedto theaction of an etching agent, such a body being preferably made bythoroughly v gr mixing together in a dry state, blanc fixe,

china clay, and an adhesive.

It is preferred to mix the blanc fixe and china clay in the proportionof two fixe to five died and ninety pounds of blanc hundred and eightypounds of china clay, free from hard and gritty or substantially freeparticles and substances, to which is add approximately sixty-fivegallons of water, and then combining with the mixture a solutionconsisting of approximately one hundred and twenty-five pounds of glue,twentyfive gallons of water, two pounds of glycerin and twelve ounces ofaluminum acetate.-

which is employed the etching, is a der, commonly "called l' hissolution causes an because ofthe fact that ochlorous acid-in the bindingquality of the thin chlorid of lime.

ily destroys York would merely be softened, with the resu ing that thepressure shade of the picture,

consists of applying to a I chlorid, or other reagents reaction, theacidity j elly I tially 3 Baum' solution;-

' etching, the'paper,

washed to remove the origithe solution readinert materials used, such asblanc fixe and If water were used, the glule t entirely unsuited forthat is required from china clay.

that the etch would be the high class of work the paper.

The alum'num acetate used in the composition because of its acidreaction with the etching. solution,

liberates an excess of the solution duractive reagent from the etchingthereby aids the process of etching, and as well as hastens the etch.

It is possible, however, to use instead of aluminum acetate, suchreagents as ferrous sulfate, copper sulfate, copper chlorid, ferrichaving an acid of which will tend to aid the etching qualities of thecoating by liberatingthe excess of the active reagent solution.

to use, in the reparatiom of the solution, those grades 0 gluecommercially known as gelatin, having a high strength, which are free orsubstanfree fromchondrin, and it is preferred over night and then heatfrom the etchin It is preferre to soak the gelatin it until in solution,aluminum acetate are added, the solution being well stirred tointimately mix the inedients. Any appropriate color may beused to impartto the-paper the required tint, and the coloring matter employed vshould be free fromlumps. A preservative, such as a volatile oil, may beadded to the glne solution. The mixture should be strained through veryfine sieves before using. The aluminum acetate solution may be made bydissolving twelve ounces of lead acetate in two quarts of water andtwelve ounces of aluminum s' fate in two quarts of water, the twosolutions being subsequently mixed together and permitted to stand. Whenthe lead sulfate has settled out on the bottom, as much as possible ofthe. solution may be poured To prevent shrinkage in the paper afterbefore the coating is ap% plied, should be nal' size,- then resized witha solution of water and caseinimixture, in the-proportion when theglycerin and this etchable of three gallons of water to two quarts ofcasein mixture. The casein mixture should contain eight ounces of orsolvent. After resizing, the paper should be put through a weak acidsolut1on,,containing one and one-half ounces of concentratedhydrochloric acid to one gallon of Water. This'treatment applies toanimal or glue sized papers. Casein and resin sized papers do not needthis treatment.

The paper mass, is calendered between the calender rolls to prodprinting surface, and is then ready for use in the printing press,thereafter being subjected to the etching process.

he etching process consists of the appli cation of an etch-proof coloreither on one side of the coated paper or on both sides, to increase theeflect; in which latter case, the printing block, with the picture to bereproduced, is supplied with prepared color ofl'ering a sulficientresistance to the etching or dissolving medium, and one or preferablyseveral exactly reglstering impressions are or pressed uce a goodprepared paper sheet having on both sides the etehable coating.

The printed sheet of prepared paper is then subjected for a short timeto the action of an etchin agent to destroy the binding qualities of t eadhesive in the etchable coating, where exposed to the actionof suchagent, and the coating, where the adhesive agent is so destroyed, isremoved by washing or brushing, so that a relief is obtainedcorresponding to the picture.

It is thus possible .to obtain, by the use of a paper coated with anetchable material of this character, strong relief values accuratelygraduated in all details, and the height of the relief may be exactlyregulated by the thickness of the coating and by the duration of theetching process.

Surfaces of the same tone are of the same height, and wh may be used asan overlayon the printing cylinder or platen, or as an underlay betweenthe printing form andthe support.

Having thus y described the nature when it has been coated with thusalways en so produced,

of my invention, what I claim as new and desire to secure by LettersPatent, is

1. In the herein described article of man ufacture, a sheet of paperhaving an etchable coating comprising blanc fixe, china clay, aluminumacetate, and an adhesive.

2. In the herein described article of manufacture, a sheet of paperhaving an etchable coating comprising blanc fixe, china clay, an agenttoaid the etching qualities of the coatlng, and an adhesive.

3. In the h ufacture, a sheet of paper having an etchable coatingcomprising blanc fixe, china clay, glycerin, aluminum acetate, and anadeslve- 4.In,}the herein described article of man-.

ufactulte, a sheet of paper having an etchable coating consisting ofblanc fixe, china clay, glue, glycerin and aluminum acetate, in theproportion of two hundred and ninety pounds of blanc fixe, five hundredand eighty pounds of china clay, one hundred and twenty-five pounds ofglue, two pounds of glycerin, and twelve ounces of aluminum acetate. v

5. In the herein described 1 article of manufacture, a sheet of paperhaving an etchable coating comprising a mineral body and aluminumacetate.

6. the herein described aluminum acetate, and an adhesive.

, In the herein described article of manufacture, a sheet of paperhaving an etchable coating comprising a mineral body, an agent to aidthe etch' mg qualities of the coatmg.

- 8. In the herein described article of man- JAMES MILN. Signed in thepresence I oil- CHAs. -ICHES, EDWARD D. BERNSTEIN.

an etcherein described article of manbody, an

comprislng a mineral body,

and

